The California National Primate Research Center translational ultrasound imaging program, a component of the Computational Imaging Core, provides state-of-the-art services and expertise in all aspects of ultrasound imaging to NIH-funded investigators. This established program is directed by a leader in the use of ultrasound imaging for nonhuman primates, and provides unique opportunities for investigators to incorporate non- invasive ultrasound-related techniques and procedures in their research, and to use non-surgical ultrasound- guided methods to develop and study monkey models of human health and disease. The goal of this proposal is to upgrade and replace an aging ultrasound imaging system that will soon reach the stage where servicing will no longer be available. This substantially undermines the reliability and imaging performance, and places the research supported by this program in jeopardy. In addition, new ultrasound imaging technologies have been developed over the past decade that are essential for this nonhuman primate translational research to remain current. The replacement ultrasound imaging system will be maintained within an established service structure led by the P.I. for this application, which has been highly effective in meeting the ultrasound imaging needs of NIH-supported investigators. This imaging system will be located within a dedicated ultrasound imaging suite in a secure environment, and with the required conditions for occupational health and safety. Funding is requested for a commercial imaging system (Philips iU22 xMATRIX) that has the features necessary for imaging nonhuman primates in all age groups (fetal to aged), and with an established reputation for equipment reliability and performance crucial for the program. With this essential replacement the California National Primate Research Center ultrasound imaging program will continue to support the high level of translational ultrasound imaging needs of NIH-funded investigators locally, regionally, and nationally.